151 resultados para 2,3-dicloro-6,7-dinitroquinoxalina


Relevância:

100.00% 100.00%

Publicador:

Resumo:

合成了 3个三环己基锡 -2 -( 1 ,2 -亚乙二硫 )亚甲基 -3-羰基 -5 -芳基 -4 -戊烯酸酯化合物 .用 IR,1 H NMR,1 3 C NMR和 1 1 9Sn NMR光谱及 X射线衍射对所合成的化合物进行了表征 .结果表明标题化合物为四配位、具有畸变四面体结构的锡酯类化合物

Relevância:

100.00% 100.00%

Publicador:

Resumo:

2,2,'3,3' -Biphenyltetracarboxylic dianhydride (2,2,'3,3'-BPDA) was prepared by a coupling reaction of dimethyl 3-iodophthalate. The X-ray single-crystal structure determination showed that this dianhydride had a bent and noncopolanar structure, presenting a striking contrast to its isomer, 3,3,'4,4'-BPDA. This dianhydride was reacted with aromatic diamines in a polar aprotic solvent such as N,N-dimethylacetamide (DMAc) to form polyamic acid intermediates, which imidized chemically to polyimides with inherent viscosities of 0.34-0.55 dL/g, depending on the diamine used. The polyimides from 2,2,'3,3'-BPDA exhibited a good solubility and were dissolved in polar aprotic solvents and polychlorocarbons. These polyimides have high glass transition temperatures above 283 degrees C. Thermogravimetric analyses indicated that these polyimides were fairly stable up to 500 degrees C, and the 5% weight loss temperatures were recorded in the range of 534-583 degrees C in nitrogen atmosphere and 537-561 degrees C in air atmosphere. All polyimides were amorphous according to X-ray determination. (C) 1999 John Wiley & Sons, Inc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

用一维 1HNMR、13CNMR方法研究了2,2′-(3,4 -四酸二酐)二苯甲酰氧基 -1,1′联萘的结构 ,并通过二维1H - 1H同核相关、13C - 1H异核相关及13C - 1H异核远程相关谱进一步地确定其1H谱和13C谱中各谱峰的归属 ,为同类化合物的表征提供了依据。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Lutetium(III) and lanthanum(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP), 3',5'-cyclic deoxyadenosine monophosphate (dcAMP) and 2',3'-cyclic adenosine monophosphate (2',3'-cAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. 2',3'-cAMP is converted to 3'-AMP and 2'-AMP, the ratio of 3'-AMP to 2'-AMP produced being 1.4.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

以1,4-萘醌为原料,经溴化、氰化、烷基化合成了1,4-二丙氧基-2,3-二氰基萘,用SiemensP4四圆衍射仪测得了晶体结构。合成方法简便,反应时间短,产率高。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

本文研究了单掺(Sm~(3+),Ce~(3+)、Gd~(3+).Sb~(3+)、双掺(Sm~(3+)+Ce~(3+)、Sm~(3+)+Gd~(3+),Sm~(3+)+Sb~(3+))和兰掺(Sm~(3+)+Gd~(3+)+Ce~(3+))约四十余种不同玻璃的发射谱和激发谱.探讨了玻璃成份和掺杂离子浓度对Sm~(3+)发光性质的影响以及Ce~(3+),Gd~(3+)、Sb~(3+)、Ce~(3+)+Gd~(3+)对Sm~(3+)的敏化作用。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

应用EI质谱和联动扫描技术研究了13个有机磷杂环化合物,讨论了主要离子的形成过程,分子离子在EI条件下的各种重排反应和取代基对不同解离反应产物离子相对强度的影响。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

二苯乙炔和正丁基锂在乙醚中反应得到中间体,使之进一步与无水氯化稀土反应得到了化合物(I),将化合物(I)与环戊二烯钠在四氢映喃(THF)中反应得到了化合物(I).通过元素分析、红外光谱、核磁共振谱和热重分析对所合成的化合物进行了鉴定,并对水解产物做了红外光谱、质谱、核磁共振谱分析.研究了铃化合物(I)与AIEt3组成的催化体系引发丁二烯聚合的反应活性,结果表明,该催化体系对丁二烯聚合有较高活性,并且溶剂和铝比对聚合活性有较大影响。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Three new (1-3) and three known (4-6) bromophenols were isolated and identified from the marine red alga Polysiphonia urceolata. On the basis of extensive analysis of spectroscopic data, the structures of these compounds were determined to be 7-bromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (1), 4,7-dibromo-9,10-dihydrophenanthrene-2,3,5,6-tetraol (2), 1,8-dibromo-5,7-dihydrodibenzo[c,e]oxepine-2,3,9,10-tetraol (3), urceolatol (4), 3-,bromo-4,5-dihydroxybenzaidehyde (5), and 3,5-dibromo-4-hydroxybenzaldehyde (6). Each of the isolated compounds was evaluated for alpha,alpha-dipheny1-beta-picrylhydrazyl (DPPH) radical scavenging activity, and all were found to be potent, with IC50 values ranging from 6.1 to 35.8 mu M, compared to the positive control, butylated hydroxytoluene (BHT), with an IC50 of 83.8 mu M.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

HS1 (haematopoietic lineage cell-specific gene protein 1), a prominent substrate of intracellular protein tyrosine kinases in haematopoietic cells, is implicated in the immune response to extracellular stimuli and in cell differentiation induced by cytokines. Although HS1 contains a 37-amino acid tandem repeat motif and a C-terminal Src homology 3 domain and is closely related to the cortical-actin-associated protein cortactin, it lacks the fourth repeat that has been shown to be essential for cortactin binding to filamentous actin (F-actin). In this study, we examined the possible role of HS1 in the regulation of the actin cytoskeleton. Immunofluorescent staining demonstrated that HS1 co-localizes in the cytoplasm of cells with actin-related protein (Arp) 2/3 complex, the primary component of the cellular machinery responsible for de novo actin assembly. Furthermore, recombinant HS1 binds directly to Arp2/3 complex with an equilibrium dissociation constant (K-d) of 880 nM. Although HS1 is a modest F-actin-binding protein with a Kd of 400 nM, it increases the rate of the actin assembly mediated by Arp2/3 complex, and promotes the formation of branched actin filaments induced by Arp2/3 complex and a constitutively activated peptide of N-WASP (neural Wiskott-Aldrich syndrome protein). Our data suggest that HS1, like cortactin, plays an important role in the modulation of actin assembly.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Two new brominated diterpenes, namely, laurendecumtriol (1) and 11-O-deacetylpinnaterpene C (2), one new polybromoindole, 2,3,4,6-tetrabromo-1-methyl-1H-indole (7), and six known natural products were isolated and identified from the marine red alga Laurencia decumbens. Their structures were elucidated on the basis of detailed spectroscopic and mass-spectrometric analysis as well as by comparison with literature data. Based on 2D-NMR experiments, the previously reported NMR data for pinnaterpene C (3) were reassigned.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since similar to 18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at similar to 11.2 cal. kyr B.P. due to a rapid rise of sea level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bolling-Allerod (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5-9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3-4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

本文在实验室内研究了温度和饵料对中华哲水蚤的生殖和生长的影响,结果表明 1)中华哲水蚤雌体的产卵模式是间歇式的,但产卵和间歇的天数因个体而异。产卵时间为1~9天不等,最长为9天;间歇时间一般为1~2天,最长为5~6天。2)中华哲水蚤雌体的产卵量对食物变化的响应为3~5天,饥饿6天后不产卵,添加饵料3天后恢复产卵。饥饿降低了雌体的生殖力,饵料质量对产卵量有明显影响。3)孵化速度随着温度的降低而减慢,18.7 ℃时达到最大孵化率时间大约为25h;16.04 ℃时约为43.5h;7 ℃时约为93.4h;当卵在3.7 ℃时,孵化率仅达到13.9%。4)根据现有的结果,NI、NII的发育时间随着温度降低而延长,7.1 ℃、9.1 ℃、15.4 ℃下以卵到NIII的发育时间约为8-9、6-7、4.5天。5)以骨条藻为饵料的幼体发育时间明显比以三角褐指藻为饵料的发育时间短,尤其在NII、NIV其表现最为明显,其中以骨条藻为饵料的中华哲水蚤的世代时间为27天。中华哲水蚤整个幼体的生长时间是不“等时”的,其中NI和NII的发育时间较短,NIII和NIV的发育时间较长,NV-CII倾向于等时生长,CII-CV发育时间又开始延长,骨条藻为饵料的世代组中,CIII的发育时间最长。6)对中华哲水蚤整个幼体的发育来说,平均生长率基本随着发育期的增长而增大。平均生长率随着饵料组分的不同而不同。2000年6月至2001年5月,在野外主要调查了南黄海(鳀鱼产卵场)中华哲水蚤的产卵率和孵化率,一年该种的总平均产卵率春季最高,夏季次之,再者冬季,秋季最长。孵化率大小范围为(75%-100%),推测中华哲水蚤的交配行为是较成功的,所调配海域为中华哲水蚤提供了较好的食物资源。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

本研究以中国对虾为材料,以杂交育种和选择育种为目标,进行了系统的中国对虾杂交育种试验、生长性状遗传参数试验及其分子遗传连锁图谱的构建工作。结果表明以不同地理群体杂交作为基础群体,然后采用系统的选择育种方法可以获得较好的选择效果。构建的遗传连锁图谱为中国对虾分子辅助育种提供一定的基础。这些试验结果为中国对虾合理系统的育种工作提供了理论基础和数据支持。其具体结果如下: 1. 试验对中国对虾黄渤海水域乳山湾群体(WYP)和朝鲜半岛南海群体(WKN)的2个群体及其杂交后代不同月龄生长情况和存活率进行了研究,测量体长(TL)、头胸甲长(CL)、头胸甲宽(CW)、第2、3腹节高(HST)、第2、3腹节宽(WST)、体重(BW)和存活率共7个性状,计算各项指标的杂种优势率,并对各性状进行了方差分析和多重比较。其3月龄生长情况和存活率研究结果表明,存活率在乳山湾群体(WYP♀)× 朝鲜半岛南海群体(WKN♂)杂交后代出现杂种劣势外,其他指标都表现出不同程度的杂种优势(4.37%~23.96% )。除了存活率外,杂交后代生长性状均显著高于亲本,乳山湾群体(WYP♀)×朝鲜半岛南海群体(WKN♂)杂交后代高于朝鲜半岛南海群体(WKN♀)× 乳山湾群体(WYP♂)杂交后代,黄渤海水域乳山湾群体高于朝鲜半岛南海群体后代。为确定测量性状与中国对虾体重的相关程度,建立了用体长(X1),头胸甲宽(X2),第2、3腹节宽(X3),头胸甲长(X4),第2、3腹节高(X5)估计体重的多元回归方程:Y = -2.056 + 0.03X1 + 0.076X2 + 0.078X3 + 0.033X4 + 0.043X5。 2. 中国对虾黄渤海水域乳山湾群体(WYP)和朝鲜半岛南海群体(WKN)2个群体及其杂交后代在4月龄时期的6个生长指标和存活率的杂种优势范围在0.514%到14.95%之间,WYP♀×WKN♂杂交后代在这7个指标中都高于WKN♀×WYP♂杂交后代。5月龄杂交后代也表现出一定程度的杂种优势,其范围在-9.000%~19.090%之间,但头胸甲长、第2、3腹节处高和存活率3个指标出现杂种劣势。不同杂交组合各个阶段生长发育情况和存活率在杂种优势表现出一定的规律。随着月龄的增加,WKN♀×WYP♂杂交后代杂种优势率有所增加,而WYP♀×WKN♂杂交后代的却有所降低。ANOVA分析结果表明,杂交后代在存活率方面与双亲差异不显著。4月龄的分析结果发现杂交后代在WST和BW这2个指标上存在显著差异。LSD多重比较结果显示,WYP♀×WKN♂杂交后代在BW指标上与亲本存在显著差异,在WST指标方面与其他3个组合的后代差异显著。5月龄的数据分析结果发现,杂交后代除体重存在显著差异外,其他各项指标差异均不显著。LSD多重比较结果发现,WKN♀×WYP♂杂交后代体重与其亲本WKN存在显著差异。 3. 对2个野生群体——朝鲜半岛南海岸群体(WKN)和黄渤海群体(WYP)和3个养殖群体——朝鲜半岛群体的养殖一代(FKN),黄海1号(HH1)和即抗98(JK98)进行杂交试验的研究,结果表明JK98 (♀)  WKN (♂)组合在存活率方面最高,其余的依次为WYP (♀) WKN (♂),WKN (♀) WYP (♂),FKN (♀)HH1 (♂) 和 WYP (♀) FKN (♂)。而在体重方面FKN(♀)  HH1(♂)组合最高,其余的依次为WKN (♀) WYP (♂),WYP (♀) WKN (♂),WYP (♀)FKN (♂) 和 JK98 (♀)WKN (♂)。在所有生长性状方面,JK98 (♀)  WKN (♂)在5个组合中是最低的。方差检测结果表明,TL、CL、HST、LL和BW这5个指标在不同组合间存在差异,而其他指标不存在差异。多重比较结果发现JK98 (♀)WKN (♂)组合的TL与其他组合间差异极显著,HST指标与WKN (♀) WYP (♂),FKN(♀)  HH1(♂)和 WYP (♀)  WKN (♂)这3个组合差异显著,BW指标与WKN (♀) WYP (♂) 和 FKN(♀)  HH1(♂)差异显著。 4. 通过人工授精的方法建立了中国对虾21个半同胞家系,测量了中国对虾21个半同胞(46个全同胞)家系的TL、CL、CW、HST、WST、第1腹节长(FL)、第6腹节长(LL)。利用MTDFREML软件得到生长性状遗传力在0.15~0.35之间,属于中度遗传力范围。TL的遗传力为0.34±0.071,CL的为0.30±0.070,CW为0.35±0.077,WST为0.33±0.073,HST为0.33±0.073,FL的最低为0.15±0.044,LL的为0.24±0.059。各个性状间表现出高的正相关,其中CW和TL以及HST的遗传相关最大,FL和WST的遗传相关最小。 通过以上杂交育种和选择育种的研究,认为单纯的依靠杂交育种来改善中国对虾的育种工作可能具有一定的局限性。所以在实际的育种过程中,以中国对虾不同群体的杂交后代作为基础群体,并以此为基础进行系统的选择育种应该具有更大的潜力。 5. 本试验利用中国对虾F2群体和AFLP分子标记技术进行了遗传连锁图谱的构建。利用55对AFLP引物组合对F2家系的110个个体进行了研究,结果检测到532个符合作图策略的AFLP标记。利用卡方检验检测分离位点是否符合孟德尔分离定律。对于符合3:1比例的分离位点利用F2自交模型构建性别平均连锁图谱,对于符合1:1比例的分离位点利用拟测交理论分别构建中国对虾的雌性和雄性遗传连锁图谱。雌性、雄性和性别平均遗传图谱分别有28、35和44个连锁群,图谱实际长度分别为1090、1617和1772.1 cM。中国对虾遗传连锁图谱估计基因组长度为2420 cM,符合与人类基因组相比的对虾类基因组长度。中国对虾雄性遗传连锁图谱比雌性遗传连锁图谱长32.6%,这可能说明中国对虾不同性别存在不同的重组率。通过皮尔逊相关系数检测认为AFLP标记在中国对虾图谱上分布均匀。本文利用AFLP标记构建的中国对虾遗传连锁图谱为中国对虾基因组研究和遗传改良提供一定的基础,同时也应该开发微卫星等共显性标记,为遗传连锁图谱的整合提供条件。

Relevância:

100.00% 100.00%

Publicador:

Resumo:

小型桡足类在生态系统中的重要作用近年来得到了广泛的关注,在近岸生态系统中,小型桡足类起着相当重要的作用。但关于小型桡足类种群动力学的研究在国内还处于起步阶段,因此我们选取了国内沿岸海域常见优势种小拟哲水蚤、双刺纺锤水蚤、太平洋纺锤水蚤及强额拟哲水蚤等四种小型桡足类为研究对象,探讨其种群动力学相关方面的变动机制。本文在2005年10月-2006年9月选取胶州湾为主要的研究海域,进行了一周年的小型桡足类的采样和培养实验研究。在胶州湾,小拟哲水蚤(Paracalanus parvus)全年出现,其种群数量变动呈现双峰型,在夏季(6月和8月)达数量高值,在冬季(1月)有一个小的高峰。种群数量在4月达全年最低值,在7月份数量也有一个明显的数量降低。从空间分布上来讲,该水蚤在冬季主要以CV期桡足幼体存在于湾南和湾外区域,湾北数量很少;从春末开始,各期幼体开始在各海区广泛分布。小拟哲水蚤在胶州湾几乎全年产卵(2月份除外),但较高的产卵率主要集中在春末到秋初,最大产卵率出现在5月,达27.9 eggs female-1d-1。总体来讲,在胶州湾小拟哲水蚤的产卵率与温度、叶绿素及体长均呈显著正相关,但与盐度呈负相关关系。从不同的区域来看,胶州湾湾北区域小拟哲水蚤产卵率较高,最高值出现在湾北6月份,产卵率达到了60.8 eggs female-1d-1。大于10 eggs female-1d-1的产卵率在湾北持续了6个月(4-9月),在湾口持续了5个月(4-8月),而在湾外只持续了3个月(5-7月)。小拟哲水蚤生物量在6月份达到最高值(6.15 mg C m-3),在4月达到全年最低值(0.028 mg C m-3)。次级生产的变动从4月到9月与生物量的变动趋势完全相似,但冬季生物量的高峰并没有伴随次级生产的高峰值,分析其原因是由于冬季低的生长率所致。小拟哲水蚤在整个胶州湾平均的年次级生产为158.41 mg C.m-3yr -1。强额拟哲水蚤(Paracalanus crassirostris)在胶州湾只在夏末到秋季出现,最大数量出现在8月份。从强额拟哲水蚤的分布区域来看,从湾内到湾外有递减趋势。在2006年9月份,只有湾北有部分种群,其他区域几乎没有该种出现。该种最大产卵率出现在8月,达11.2 eggs female-1d-1。强额拟哲水蚤生物量的变动与次级生产的变动趋势相似,最大值也都出现在8月份。该水蚤在胶州湾平均年次级生产仅为2.12 mg C m-3yr-1。双刺纺锤水蚤(Acartia bifilosa)在胶州湾是全年出现,其种群数量在5-6月份突发性增加达全年最高值(>8000 ind. m-3),之后又急剧下降。从该种的区域分布来看,5-6月份数量的高峰主要出现在湾北区域,7月份虽然各区域数量均下降,但大部分种群集中在湾外区域。双刺纺锤水蚤在胶州湾几乎全年产卵(1-2月除外),产卵率的最高值出现在4月,达16.5 eggs female-1d-1。4月份雌体高的产卵率为5月份种群数量的大量增加提供了补充。双刺纺锤水蚤生物量与次级生产的变动趋势一致,在5-6月份达到高值,在秋冬季次级生产较低。双刺纺锤水蚤在整个胶州湾平均的年次级生产为114.61 mg C m-3yr-1。太平洋纺锤水蚤(Acartia pacifica)在胶州湾季节性出现,在冬春季节消失,从夏季开始出现。该种在5月零星出现,种群数量在6月份开始增多,到7月份达到最高值2356 ind. m-3,之后在8月数量锐减至196 ind. m-3。从区域分布来看,该水蚤在胶州湾只出现在湾北和湾南区域,湾外区域几乎没有,而且呈现湾北到湾南递减的趋势。6月份数量大部分出现在湾北区域,到7月份才有一部份在湾南出现。太平洋纺锤水蚤在其出现季节均产卵,最大产卵率出现在6月份,达37.17 eggs female-1 d-1,部分补充了7月份太平洋纺锤水蚤种群数量的大量增加。太平洋纺锤水蚤生物量与次级生产的变动趋势相似,在7月份达到了最高值,在11月达到最低值。太平洋纺锤水蚤在胶州湾平均的年次级生产为45.63 mg C m-3yr-1。胶州湾四种小型桡足类总的年次级生产为~320 mg C m-3 yr-1。